Browse free open source Calculators and projects for Windows below. Use the toggles on the left to filter open source Calculators by OS, license, language, programming language, and project status.

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  • 1
    PeaZip

    PeaZip

    Free Zip software and Rar extractor

    PeaZip is a free archiver tool. The application provides an unified, natively portable, cross-platform file manager and archive manager GUI for many Open Source technologies like 7-Zip, FreeArc, PAQ, UPX. Create: 7Z, ARC, Brotl, BZip, GZip, PEA, TAR, WIM, XZ, ZPAQ, ZIP, Zstandard files and more Open and extract 200+ file types: ACE, CAB, DEB, ISO, RAR, ZIPX and more Features of PeaZip includes extract, create and convert multiple archives at once, create self-extracting archives (sfx), split files, strong encryption with two factor authentication, encrypted password manager, secure deletion, find duplicate files, calculate hashes, export task definition as command line script.
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    Downloads: 4,367 This Week
    Last Update:
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  • 2
    Windows Calculator

    Windows Calculator

    A simple yet powerful calculator that ships with Windows

    Calculator is the open source version of the Microsoft Windows Calculator application. It is a modern Windows app written in C++ and C#, offering standard, scientific, and programmer modes, unit/currency conversion, date calculations, and history/memory operations. It ships preinstalled with Windows and is actively developed on GitHub. Standard Calculator functionality, which offers basic operations and evaluates commands immediately as they are entered. Scientific Calculator functionality, which offers expanded operations and evaluates commands using the order of operations. Programmer Calculator functionality, which offers common mathematical operations for developers, including conversion between common bases.
    Downloads: 95 This Week
    Last Update:
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  • 3

    TILP - TI Linking Program

    TI graphing calculators <-> computer communication software

    TILP (formerly GtkTiLink) can transfer data between Texas Instruments graphing calculators and a computer. It works with all link cables (parallel, serial, Black/Gray/Silver/Direct Link) and it supports the TI-Z80 series (73..86), the TI-eZ80 series (83PCE, 84+CE), the TI-68k series (89, 92, 92+, V200, 89T) and the Nspire series (Nspire Clickpad / Touchpad / CX, both CAS and non-CAS). The project is now managed on Github, https://github.com/debrouxl/tilp_and_gfm . It uses the libti* libraries, https://github.com/debrouxl/tilibs . Install script for *nix: https://github.com/debrouxl/tilp_and_gfm/blob/master/tilp/trunk/build/scripts/install_tilp.sh
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    Downloads: 436 This Week
    Last Update:
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  • 4
    Integrated Development Environment for some microcontrollers based on 8051(e.g. AT89S8253). Supported languages are Assembly and C. It has its own simulator, assembler, editor and many other tools. See the project web site for more details and the newest updates.
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    Downloads: 450 This Week
    Last Update:
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  • 5
    CRC RevEng

    CRC RevEng

    Arbitrary-precision CRC calculator and algorithm finder

    CRC RevEng is a portable, arbitrary-precision CRC calculator and algorithm finder. It calculates CRCs using any of the 113 preset algorithms, or a user-specified algorithm to any width. It calculates reversed CRCs to give the bit pattern that produces a desired forward CRC. CRC RevEng also reverse-engineers any CRC algorithm from sufficient correctly formatted message-CRC pairs and optional known parameters. It comprises powerful input interpretation options. Compliant with Ross Williams' Rocksoft(tm) model of parametrised CRC algorithms.
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    Downloads: 375 This Week
    Last Update:
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  • 6
    Open Tax Solver

    Open Tax Solver

    Calculates income tax form entries, helps do your taxes.

    OTS is a safe, secure, easy-to-use program for calculating Tax Return Form entries, and determining your tax-owed or refund-due, for Federal or State personal income taxes. Includes updated versions for US 1040, Schedules A, B, C, D, and for several states. OTS provides both graphical and textual interfaces for quickly filing out your tax forms. --- Best way to download the correct version for your platform -- go to the OTS WEBSITE: =====> https://opentaxsolver.sourceforge.net/
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    Downloads: 217 This Week
    Last Update:
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  • 7
    teemIP - CMDB & DDI solution

    teemIP - CMDB & DDI solution

    teemIP : Open source IPAM & DDI solution with CMDB integration.

    teemIP is an open source, web-based IP Address Management (IPAM) and DDI solution built on the iTop framework. It provides comprehensive IP management: IPv4/IPv6 plan management, subnet hierarchy, IP lifecycle, VLAN and DNS/DHCP integration. teemIP is now maintained by the teemIP SAS founding team: Christophe Naud (original creator), Martin de Laval and Quentin Ville. The company is being officially incorporated in July 2026. The project remains open source under AGPL v3. Professional support, integration services and subscriptions: https://www.teemip.com
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    Downloads: 132 This Week
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  • 8
    Nano ID

    Nano ID

    A secure, URL-friendly, unique string ID generator for JavaScript

    Nano ID is a library for generating random IDs. Likewise UUID, there is a probability of duplicate IDs. However, this probability is extremely small. Meanwhile, a lot of projects generate IDs in small numbers. For those projects, the ID length could be reduced without risk. This calculator aims to help you realize the extent to which the ID length can be reduced. Instead of using the unsafe Math.random(), Nano ID uses the crypto module in Node.js and the Web Crypto API in browsers. These modules use unpredictable hardware random generator. Uniformity, random % alphabet is a popular mistake to make when coding an ID generator. The distribution will not be even; there will be a lower chance for some symbols to appear compared to others. So, it will reduce the number of tries when brute-forcing. Nano ID uses a better algorithm and is tested for uniformity.
    Downloads: 15 This Week
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  • 9
    CEmu emulator

    CEmu emulator

    Third-party TI-84 Plus CE / TI-83 Premium CE emulator

    Developer-oriented emulator of the eZ80-based TI-84 Plus CE / TI-83 Premium CE calculators. CEmu is a third-party TI-84 Plus CE / TI-83 Premium CE calculator emulator, focused on developer features. The core is programmed in C and the GUI in C++ with Qt, for performance and portability reasons. CEmu works natively on Windows, macOS, and Linux! Easy setup - get running by doing a one-time-only connection of your calculator! Accurate and fast emulation. Customizable speed/throttling. Resizable calculator screen. "Always-on-top" window option. Screen capture (PNG). Screen recording (animated PNG). File sending/receiving (not for Apps/OS yet). Multiple keybinding presets. Emulation states for efficient saving / restoring. Color skins (like the real devices). Available in English, French, Spanish, and Dutch.
    Downloads: 14 This Week
    Last Update:
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  • 10
    Precise Calculator
    Precise Calculator has arbitrary precision and can calculate with complex numbers, fractions, vectors and matrices. Has more than 150 mathematical functions and statistical functions and is programmable (if, goto, print, return, for).
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    Downloads: 63 This Week
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  • 11
    Calculator to compute message digests, checksums for files, as well as for text and hex strings.
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    Downloads: 176 This Week
    Last Update:
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  • 12
    GestioIP IPAM - IP address management
    An automated, Web based IP address management (IPAM) software. It features powerful search and filter functions for both networks and host, as well as many tools (e.g. a subnet calculator) helping Administrators to plan and handle complex IP networks
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    Downloads: 54 This Week
    Last Update:
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  • 13
    WP 34s

    WP 34s

    Scientific/engineering firmware repurposing HP business calculators!

    This project has created scientific firmware for the HP-20b and HP-30b business calculators. WP 34S turns either of these calculators into a powerful keystroke programmable scientific device. According to our customers, it's the most powerful and fastest RPN scientific pocket calculator ever built. WP 34S is alive and stable since 2011. We have succeeded in satisfying the most picky users - read about their experiences on http://www.hpmuseum.org/forum/forum-8.html. Since 2014, WP 34S runs in version 3.3. Our customers confirm its documentation is excellent and comprehensive (see feedback); a full-color printed edition is available from https://www.amazon.com/dp/153366238X since 2018-10-15. Alternatively, you can get a personalized pdf-manual for a ≥ 9 US$ donation here. We have also produced the WP 31S which is derived from the WP 34S source code. This is an entry-level scientific calculator. Its printed manual is available from https://www.amazon.com/dp/1499231164 .
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    Downloads: 39 This Week
    Last Update:
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  • 14

    ATCalc

    Programming environment. Scientific and graphic calculator.

    From single or scientific calculator to structured programming environment (+- pascal): Input, graphic (display of functions; direct draw; display, capture, etc. of images) functions; tests, ... Ready: visual problems or blind users. See below in the web (http://atcalc.sourceforge.net/)
    Downloads: 29 This Week
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  • 15
    GraphCalc is a very gui graphing calculator. It has been called a good replacement for a TI-85. It is a must for any high school math student.
    Downloads: 17 This Week
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  • 16
    Finanx 12c

    Finanx 12c

    Financial Calculator

    The Finanx 12c is a free software that mimics the HP-12C financial calculator. This software was developed for educational purposes. IT'S NOT RECOMMENDED using this calculator for professional calculations. If you find any bugs, please, let me know. Click "Bugs" in the menu bar to report bugs found.
    Downloads: 16 This Week
    Last Update:
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  • 17
    'atlc' is a CAD package used for analysing and desiging electrical transmission lines of arbitrary cross section. Also for the design of directonal couplers. Some parts are CPU intensive, so multiple CPUs are supported.
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    Downloads: 26 This Week
    Last Update:
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  • 18
    fHash

    fHash

    A files hash calculator for Windows and macOS.

    An open source files hash calculator for Windows and macOS. * MD5, SHA1, SHA256 and SHA512. * Drag & drop. * Integrated with context menu in Explorer/Finder. * Support Windows 7 and later. * Support macOS 13 and later, with universal binary. * Support Dark Mode. * English and Simplified Chinese UI. The icon "希" is from hash in Chinese "哈希".
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    Downloads: 40 This Week
    Last Update:
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  • 19
    Advanced Trigonometry Calculator

    Advanced Trigonometry Calculator

    Open-source C/C++ math engine for advanced scientific computing

    Advanced Trigonometry Calculator (ATC) is an open-source mathematical computing engine written mainly in C/C++. Created in 2011 and maintained by Renato Alexandre dos Santos Freitas, ATC is designed as a practical Windows desktop application for advanced calculations, automation, and technical problem solving. ATC supports equation solving, polynomial tools, complex numbers, matrix calculations, statistics, physics, geometry, unit conversions, DSP/FFT operations, and scripting. It can also process batch TXT files, making it useful for repeatable calculations and automated workflows. The project also includes ATC Online Alpha, a WebAssembly-based version that brings parts of the ATC engine to the web. ATC is released under the GPLv3 license and is made in Portugal.
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    Downloads: 23 This Week
    Last Update:
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  • 20
    Smith Chart Calculator

    Smith Chart Calculator

    Smith Chart Calculator JAVA

    A small tool which allows all basic smith chart actions. This program was created for educational purposes. JAVA RUNTIME REQUIRED Tested on Windows. Some features may not available with other OS (e.g. copy to clipboard) GENERAL PUBLIC LICENSE There is a pdf help file online take a look in the files section. There is also a link available in the program itself.
    Downloads: 23 This Week
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  • 21
    Calculator-Scripts

    Calculator-Scripts

    Just a few scripts for pocket calculators.

    Just a few applications for various pocket calculators.
    Downloads: 64 This Week
    Last Update:
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  • 22
    4tH compiler

    4tH compiler

    A friendly Forth compiler with a little difference

    4tH is a Forth compiler with a little difference. Instead of the standard Forth engine it features a conventional compiler. 4tH is a very small compiler that can create bytecode, C-embeddable bytecode, standalone executables, but also works fine as a scripting language. It supports about 95% of the ANS Forth CORE wordset and features conditional compilation, pipes, files, assertions, forward declarations, enumerations, structures, suspended execution, recursion, include files, etc. It comes with an RPN calculator, BASIC interpreter, line editor, preprocessor, compiler, decompiler, C-source generator, a virtual machine, and a multitasking environment.
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    Downloads: 62 This Week
    Last Update:
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  • 23
    Gordian Knot started out as a simple bitrate calculator for DivX encoding but has evolved to become an integrated package or tool for the entire process of DivX/XviD encoding.
    Downloads: 13 This Week
    Last Update:
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  • 24
    Numi

    Numi

    Beautiful calculator app for macOS

    Numi is a handy calculator app for macOS. It allows you to describe tasks naturally and instantly get an answer. For example, $20 in euro - 5% discount or today + 2 weeks.
    Downloads: 2 This Week
    Last Update:
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  • 25

    Geometry Dashboard

    A project to create a simple Geometry Calculator

    I apologize for this, but an accident occurred and all of my GeoDash work has been lost. No updates will be coming. To view all of the files available please click on the 'Browse All Files' link under the 'Big Green Download' button above this description.
    Downloads: 29 This Week
    Last Update:
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